Treatment of distillate feed



May 15 1961 J. G. PORTER, JR., ErAL 2,984,614

TREATMENT OF DISTILLATE FEED Filed Sept. 6, 1957 United States Patent Oee 2,984,614 Patented May 16, 1961 TREATMENT F DISTILLATE FEED John G. Porter, Jr., and Paul R. Walton, Pitman, NJ.,

assgnors to Socony Mobil 'Oil Company, Inc., a corporation of New York Filed Sept. 6, 1957, Ser. No. 682,541

3 Claims. (Cl. 208-60) The present invention .relates to the improvement of the diesel index `of distillate fuels and to the preparation of improved feed for a reforming unit.

yIn the past it has been the most common practice to prepare distillate fuels `of adequate diesel index by the judicious selection and blending of stocks available at each refinery. Generally, this has consisted of upgrading catalytic distillates by blending with straight run distillates. More recently, the diesel index of these distillates has been improved somewhat by hydrofningprimarily a hydrodesulfurization process. However, hydroning as usually practiced does not produce a fuel having a greatly increased diesel index. On the other hand, the diesel index of distillate fuels is improved by extraction with solvents for the more aromatic constituents of the fuels but such extraction produces an extract which boils above the boiling range of gasoline. The extract when cracked in the absence of hydrogen to produce a gasoline does not provide a gasoline having an octane rating such as is now demanded by the motoring public. The gasoline produced by cracking the extract in the absence of hydrogen also is not a desirable feed for a reforming unit because of its olefin content. Thus, present practice has not provided an economically attractive method for producing distillate fuels having a high diesel index.

Before describing the `present invention it is believed desirable to define certain terms as used herein. Thus, a distillate fuel is a hydrocarbon mixture having a boiling range of about 350 F. to about 650 F. Such a distillate fuel can be a straight run distillate prepared by distillation of the crude or a distillate obtained from a conversion process, e.g., catalytic cracking, thermal cracking, coking, visbreaking, etc.

The diesel index of a distillate fuel such as produced by catalytic cracking usually is about 15 to about 35. The diesel index of hydrocracked distillate fuel is usually about 45 to about 65. The diesel index of a distillate fuel produced .in accordance with the principles of the present invention usually is about 45 to about 65.

In addition to the production of a distillate fuel of improved diesel index, the present invention provides a means for producing an improved reforming stock which can readily be reformed to 10 RVP gasoline having octane ratings (Research 3 cc. TEL) in excess of 100.

Illustrative of the present invention is the block diagram of the drawing. A distillate fuel having a boiling range above the gasoline boiling range and usually from about 350 F. to about 650 F. and having a diesel index of about l5 to about 35 is extracted with a solvent for aromatic hydrocarbons such as sulfur dioxide, diethylene glycol, triethylene glycol, ethylene carbonate, etc. to produce a ramate of improved diesel index, e.g., of about 45 to about 65 The ratio of solvent to distillate fuel is dependent upon the solvent employed and the extraction temperature and is well known to those skilled in the art. The extract is freed from solvent, heated to reaction temperature at reaction pressure, and contacted with a hydrocracking catalyst in the presence of hydrogen. Hydrocracking of the aromatic hydrocarbons recovered from the extract results in the lowering of the boiling range of the extracted aromatic hydrocarbons by removal of one or more side chains. In addition, the aromatic nucleus is hydrogenated to some extent. Any suitable catalyst having cracking as well as hydrogenating activity can be employed. Suitable hydrocracking catalysts include a mixture of cobalt and molybdenum oxides an an alumina support, platinum acidic oxide catalysts, for example, those which include between about 0.05 percent and about 20 percent, by Weight, of the catalyst, of at least one metal of the platinum and palladium series deposited upon a synthetic composition of two or more refractory oxides, said composition having an activity index of at least 25. The synthetic composites of refractory oxides can also contain halogens and other materials which are known in the art as promoters for cracking catalysts. The synthetic composites can also contain small amounts of alkali metals added for the purpose of controlling the activity index of the carrier. Non-limiting examples of the synthetically-produced composites include silicaalumina, silica-zirconia, silica-alumina-zirconia, silicaalumina-thoria, alumina-boria, silica-magnesia. silicaalumina-magnesia, silica-alumina-iluorine and the like. A preferred support is a synthetic composite of silica and alumina which contains between about l and about percent, by weight, of alumina. Hydrocracking conditions are as follows:

Broad Preferred Reactor Temperature, "F 60G-950 750-900 Reactor Pressure, psig 50G-5i, 000 500-2, 000 Hydrogen to oil mol ratio 10-10 20-50 Hydrogen content of recycle gas 50-100 70-100 Space Velocity, v./v./hr 0. l-5 0. 5-3

[Catalyst: 0.1-1 weight percent platinum on alumina] Broad Preferred Reactor Temperature, F 800-1, 050 S50-980 Reactor Pressure, p.s.i.g. 0-800 25-750 Hydrogen to oil mol ratio-- 1-10 5-10 Space Velocity, v./v./hr 0.1-10 0. 5-5

The reformer eiuent is separated into a recycle gas comprising hydrogen and C1 to C4 hydrocarbons and a reformate comprising C44-hydrocarbons.

The hydrogen-containing recycle gas separated from the effluent of the hydrocracker can be treated for the removal of hydrogen sulfide continuously or when the concentration of these and other hydrogen derivatives of sulfur, nitrogen, arsenic, etc. has a deleterious effect upon the hydrocracking catalyst. The recycle gas separated from the eluent of the hydrocracker is returned to the hydrocracker. Since the amount of hydrogen produced in the reformer is generally more than is required to maintain the required hydrogen to oil mol ratio in the reformer, the excess reformer recycle gas can be used in the hydrocracking reactor as required.

The hydrogen-containing recycle gas separated from the effluent from the reformer is recycled in part to the reformer to maintain the required hydrogen to oil ratio and the balance sent to the hydrocracker or other hydrogen consuming processes.

We claim:

1. A method of upgrading distillate fuel and producing 10 RVP gasoline having an octane rating in excess of 95 (Research-|-3 cc. TEL) which consists esssentially of contacting a distillate fuel having a diesel index of about 15 to about 35 and comprising paraflinic and aromatic hydrocarbons and boiling within the range of about 350 F. to about 650 F. with a solvent for aromatic hydrocarbons to produce a paraffinic raffinate and an aromatic extract, separating said raffinate from said extract, removing solvent from said ranate to produce upgraded distillate fuel having a diesel index of at least 45, removing solvent from said extract to produce hydrocracker feed comprising aromatic and naphthenic hydrocarbons substantially devoid of solvent, contacting said hydrocracker feed in a hydrocracking reaction Zone with a hydrocracking catalyst in the presence of hydrogen under hydrocracking conditions of temperature, pressure, and liquid lhourly space velocity to produce hydrocracker eiuent, separating said hydrocracker eiuent into hydrocracker recycle gas comprising hydrogen and C1 to C., hydrocarbons and reformer feed comprising C5 and heavier hydrocarbons, recycling at least a portion of said hydrocracker recycle gas to said hydrocracking reaction zone, contacting the aforesaid reformer feed in a reforming reaction zone with reforming catalyst in t-he presence of hydrogen under reforming conditions of temperature, pressure, and liquid hourly space velocity to produce reformer effluent, separating said reformer eiuent into reformer recycle gas comprising hydrogen and C1 to C4 hydrocarbons, and reformate comprising C5 and heavier hydrocarbons having a required octane rating, and recycling at least a portion of said reformer recycle gas to the aforesaid reforming reaction Zone as the sole source of hydrogen introduced thereinto.

2. The method of upgrading distillate fuel and producing RVP gasoline having an octane rating in excess of 95 (Research-F3 cc. TEL) as set forth and described in claim 1 wherein said hydrocracker feed is contacted with platinum-group metal hydrocracking catalyst,

4 wherein the hydrocracking reaction temperature isY within the range of about 600 to about 950 F. and wherein the liquid hourly space velocity is 0.1 to 10.

3. The method of upgrading distillate fuel and producing 10 RVP gasoline having an octane rating in excess of (Research-H cc. TEL) as set forth and described in claim 1 wherein the hydrocracker feed is the extract, substantially devoid of solvent, from at least one distillate fuel oil selected from the group consisting of straight run, catalytically cracked, thermally cracked, coker, and visbreaker, distillate fuel oils wherein said hydrocracker feed is contacted with platinum-group metal hydrocracking catalyst comprising about 0.05 to about 20 percent by weight of at least one metal of the platinum and palladium series deposited upon a synthetic composition of two or more refractory oxides, wherein the hydrocracking reaction Zone temperature is within the range of about 600 to about 950 F., wherein the hydrocracking reaction Zone pressure is within the range of about 500 to 5000 p.s.i.g., wherein the liquid hourly hydrocracking space velocity is within the range of about 0.1 to 5, wherein the reformer feed is contacted in the reforming reaction zone with platinum-group metal reforming catalyst comprising 0.1 to l percent by weight platinum on alumina, wherein the reforming reaction zone temperature is Within the range of about 800 to about 1050" F., wherein the reforming reaction zone pressure is within the range of about 0-800 p.s.i.g., wherein the liquid hourly reforming space velocity is within the range of about `0.1 to about 10, wherein a portion of the reformer recycle gas is introduced into the hydrocracking reaction zone, and wherein the reformer feed is reformed to produce 10 RVP gasoline having an octane rating in excess of 95 (Research-|-3 cc. TEL).

References Cited in the file of this patent UNITED STATES PATENTS 2,397,329 Ruthruif Mar. 26, 1946 2,429,875 Good et al. Oct. 28, 1947 2,431,920 Cole Dec. 2, 1947 2,608,470 Helmers et al Aug. 26, 1952 2,644,785 Harding et al July 7, 1953 2,697,681 Murray et al. Dec. 21, 1954 2,697,684 Hemminger et al Dec. 21, 1954 2,703,308 Oblad et al. Mar. 1, 1955 2,768,119 Nash Oct. 23, 1956 2,769,769 Tyson Nov. `6, 1956 

1. A METHOD OF UPGRADING DISTILLATE FUEL AND PRODUCING 10 RVP GASOLINE HAVING AN OCTANE RATING IN EXCESS OF 95 (RESEARCH+3 CC. TEL) WHICH CONSISTS ESSENTIALLY OF CONTACTING A DISTILLATE FUEL HAVING A DIESEL INDEX OF ABOUT 15 TO ABOUT 35 AND COMPRISING PARAFFINIC AND AROMATIC HYDROCARBONS AND BOILING WITHIN THE RANGE OF ABOUT 350*F. TO ABOUT 650*F. WITH A SOLVENT FOR AROMATIC HYDROCARBONS TO PRODUCE A PARAFFINIC RAFFINATE AND AN AROMATIC EXTRACT, SEPARATING SAID RAFFINATE FROM SAID EXTRACT, REMOVING SOLVENT FROM SAID RAFFINATE TO PRODUCE UPGRADED DISTILLATE FUEL HAVING A DIESEL INDEX OF AT LEAST 45, REMOVING SOLVENT FROM SAID EXTRACT TO PRODUCE HYDROCRACKER FEED COMPRISING AROMATIC AND NAPHTHENIC HYDROCARBONS SUBSTANTIALLY DEVOID OF SOLVENT, CONTACTING SAID HYDROCRACKER FEED IN A HYDROCRACKING REACTION ZONE WITH A HYDROCRACKING CATALYST IN THE PRESENCE OF HYDROGEN UNDER HYDROCRACKING CONDITIONS OF TEMPERATURE, PRESSURE, AND LIQUID HOURLY SPACE VELOCITY TO PRODUCE HYDROCRACKER EFFLUENT, SEPARATING SAID HYDROCRACKER EFFLUENT INTO HYDROCRACKER RECYCLE GAS COMPRISING HYDROGEN AND C1 TO C4 HYDROCARBONS AND REFORMER FEED COMPRISING C5 AND HEAVIER HYDROCARBONS, RECYCLING AT LEAST A PORTION OF SAID HYDROCRACKER RECYCLE GAS TO SAID HYDROCRACKING REACTION ZONE, CONTACTING THE AFORESAID REFORMER FEED IN A REFORMING REACTION ZONE WITH REFORMING CATALYST IN THE PRESENCE OF HYDROGEN UNDER REFORMING CONDITIONS OF TEMPERATURE, PRESSURE, AND LIQUID HOURLY SPACE VELOCITY TO PRODUCE REFORMER EFFLUENT, SEPARATING SAID REFORMER EFFLUENT INTO REFORMER RECYCLE GAS COMPRISING HYDROGEN AND C1 TO C4 HYDROCARBONS, AND REFORMATE COMPRISING C5 AND HEAVIER HYDROCARBONS HAVING A REQUIRED OCTANE RATING, AND RECYCLING AT LEAST A PORTION OF SAID REFORMER RECYCLE GAS TO THE AFORESAID REFORMING REACTION ZONE AS THE SOLE SOURCE OF HYDROGEN INTRODUCED THEREINTO. 